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Updated: May 4, 2025
Darwin abundantly demonstrates the variability of dogs, horses, fowls, and pigeons, but he none the less shows clearly the very small extent to which the goose, the peacock, and the guinea-fowl have varied. Mr. Darwin attempts to explain this fact as regards the goose by the animal being valued only for food and feathers, and from no pleasure having been felt in it on other accounts.
Variability Individual differences Doubtful species Wide ranging, much diffused, and common species, vary most Species of the larger genera in each country vary more frequently than the species of the smaller genera Many of the species of the larger genera resemble varieties in being very closely, but unequally, related to each other, and in having restricted ranges.
Two opinions have been advanced to explain this high degree of variability, but neither of them conveys a real explanation; their aim is chiefly to support different views as to the causes of variability, and the origin of elementary species at large.
I am aware that the transformation of one species into another has not yet been effected, but the above-mentioned attempts at transformation have nevertheless demonstrated that certain organic forms when subjected to changed conditions of life, display certain mutations which clearly show that variability is to be attributed, not, certainly, to the specific concepts, but to the corresponding reality.
Variability is not actually caused by man; he only unintentionally exposes organic beings to new conditions of life and then nature acts on the organisation and causes it to vary. But man can and does select the variations given to him by nature, and thus accumulates them in any desired manner. He thus adapts animals and plants for his own benefit or pleasure.
But the mere existence of individual variability and of some few well-marked varieties, though necessary as the foundation for the work, helps us but little in understanding how species arise in nature. How have all those exquisite adaptations of one part of the organisation to another part, and to the conditions of life and of one organic being to another being, been perfected?
It is probable that the successive variations in strength, size, and courage, whether due to mere variability or to the effects of use, by the accumulation of which male quadrupeds have acquired these characteristic qualities, occurred rather late in life, and were consequently to a large extent limited in their transmission to the same sex. Accordingly, I applied to Mr.
He never made a single step to withdraw himself from that authority. He rather prides himself on having never allowed himself, by any philosophy, to be turned away from his first and natural sic opinions, and from the condition in which God had placed him; being well aware of his own variability volubilite.
A great amount of variability, under which term individual differences are always included, will evidently be favourable. A large number of individuals, by giving a better chance within any given period for the appearance of profitable variations, will compensate for a lesser amount of variability in each individual, and is, I believe, a highly important element of success.
It has been seen in the last chapter that amongst organic beings in a state of nature there is some individual variability; indeed I am not aware that this has ever been disputed.
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